Evidently, there are 2 companies manufacturing skyscraper puzzles, there's Puzz3D and more recently, Cubic Fun Puzzles. Both seem to be similar, using paper glued to foam. Neither require glue or painting. The Cubic Fun model puzzles are often cheaper and the skyscrapers often overlap made by both. Both make the Empire State, Chrysler, and more. I prefer Cubic Fun as they have a wider selection, cost less (Empire State is only $12). My only complaint with Cubic Fun Puzzles is the instructions are very unclear. For example, the Burj Khalifa, which is complex to begin with, doesn't help with confusing construction diagrams. After over 30 hours of aggravation, I finally completed it. It's over 5 feet high and so beautiful but those instructions!